DE2944113A1 - METHOD AND DEVICE FOR THE QUANTITATIVE ABSOLUTE DETERMINATION OF OPTICALLY ACTIVE SUBSTANCES - Google Patents

Abstract

1. A process for the quantitative determiantion of a dissolved optically active substance in aqueous or non-aqueous solutions by means of polarimetry by splitting the light beam after the sample by means of a beam splitter, thereby producing a measuring beam and a reference beam, and forming a difference or quotient signal of the signals of the measuring and the reference beam detected by corresponding detectors, whereby the polarized light of the light source prior to passing through of the sample is eventually subjected to frequency, phase, or amplitude modulation, and the difference or quotient signal formed of the signals of the measuring and the reference beam is demodulated correspondingly, characterized in that for simultaneously obtaining beam splitting and an analyzing effect the light beam after the sample is directed to an optical interface at an incidence angle (alpha) between the polarization angle and the limit angle of total reflection.

Description

29U113

Dr. Arno Müller
D-7900 Ulm-Mähringen

Method and device for quantitative
Absolute determination of optically active substances

The invention relates to a highly sensitive method
for quantitative Absolutbestiramung optically active substances even in very low concentrations in aqueous or non aqueous _w solutions, for example glucose or fructose in the blood, plasma or serum, as well as an apparatus therefor.

According to the invention, the analysis can be carried out both in vivo, ie directly on or in the living organism, and in vitro will. It is already known that the glucose concentration, mostly in serum, either enzymatically or, for example, by visual colorimetry, titrimetry or photometry can be determined (picric acid method, glucose oxidase, perodase, hexokinase method). From the

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DE-OSes 2 200 119 and 2 326 265 is also known that a fuel cell is implanted in a living organism a telemetric device can be used to record some characteristic measured values (e.g. the pH value, the glucose concentration, etc.) into electrical signals. It has also already been suggested that Blood glucose concentration by measuring the absorption of a beam of light in the blood at a specific wavelength to be determined (see US Pat. No. 3,958,560; N. Kaiser, Optics Communication 1-17, No. 2 (1974) 175). Such However, because of the large number of absorption bands of organic molecules, measurements are fundamentally difficult opposite.

DE-OS 2 724 543 also discloses the glucose concentration to be measured polarimetrically in vitro or in vivo.

However, since in the polarimetric determination of glucose in the blood, for example, the presence of other optically active substances causes a background rotation that is superimposed on the glucose-related rotation value, this method only allows relative measurements. In addition, the outlay on equipment is relatively high due to the required high measurement sensitivity of 10 "^ to 10 ~ ^{δ °.}

The invention is based on the object of providing a highly sensitive, rapid and reproducible method as well a corresponding device for the quantitative analysis of optically active substances, even in very small concentrations in aqueous or non_, aqueous and in particular biochemical and biological systems to indicate the for the absolute measurement of the concentration of an optically

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even
active component / in the presence of other optically active substances.

The method is also intended for direct in vivo measurement the blood glucose level, for example in diabetics, for example in a transcutaneous and / or injury-free way be suitable.

The device according to the invention should be based on a simple apparatus concept and an absolute measurement of the Concentration of an optically active substance also in the presence of other optically active substances with a different one Allow time-concentration behavior and not the limited sensitivity of conventional devices exhibit. Furthermore, the device should not only be able to be used stationary, but also be sufficiently small and easy to implement due to their concept, so that they can, for example worn on the body or partially or fully implanted in it.

The problem is solved according to the claims.

In the subclaims are advantageous embodiments specified.

The method according to the invention does not have the serious disadvantage of conventional methods that only relative measurements the concentration of an optically active substance in the presence of other substances with optical activity are possible, and for the first time allows absolute determinations, especially a direct, injury-free one transcutaneous determination of the blood glucose level.

The inventive method for quantitative

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Determination of dissolved optically active substances in aqueous or non-aqueous solutions, in particular for in vivo determination the blood glucose level, by polarimetry below

- irradiation of the sample with linearly polarized light,

- Splitting of the light beam after passing through the sample with a beam splitter into a hot beam and a reference beam,

- Measurement of the intensity of the measuring beam and the reference beam with a detector,

- Generation of a difference or quotient signal from the Hess and reference signals

and

- Final amplification of the resulting signal for display or registration

is characterized in that for absolute determination at least one optically active substance in the presence of other optically active substances with different Concentration change frequencies

the signal component (s) with the concentration change frequency from the resulting difference or quotient signal the optically active substance (s) to be determined are separated from the remaining signal components.

According to an advantageous development of the method according to the invention, the signal is divided by frequency band separation performed. A high or low pass filter or a band pass filter can be used for this purpose. The signal division can also be achieved by differentiation, the use of a high or low pass and subsequent

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Integration can be made. It is also advantageous to compensate for any background rotation that may be present by adding a direct current component.

The method according to the invention can be applied to all systems where the change in the concentration of the optically active substances over time and thus the change over time Changes in the corresponding increments of the optical rotation value are sufficiently different from one another. the Separability of the rotation value components belonging to the individual optically active substances depends on the Slope of the attenuation curve of the bandpass used for frequency band separation. With the usual RC elements For example, frequencies that differ from one another by a factor of 1.5 can still be used easily separate from each other for signal division. However, this factor is not a limit value.

The duration of the measurement depends on the frequency of change in concentration of the optically active components to be determined.

te off. At an average frequency of around 10 Hz

4 results in a period of 10 s and thus a minimum measurement period of about 3 h.

The concept according to the invention is explained in more detail below with reference to the in vivo glucose atmosphere.

The difficulty of separating the polarimetrically measured glucose-related rotation value from that by proteins, Background rotation caused by cholesterol and lipids "can according to the invention as a result of the very different temporal Concentration course of these blood components are overcome.

The concentration of glucose in the blood changes with one maximum frequency of about 8 χ 10 * "^ Hz, while the Concentration of proteins and blood lipids normally changes with a maximum frequency of about ΙΟ "- * Hz.

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Because of this different behavior, according to the invention the corresponding measured values are separated during signal processing.

Through frequency band separation, for example through differentiation and subsequent integration or Differentiation of the signal voltage, signal division to separate the low frequencies (high pass) and Subsequent integration, possibly with the addition of a direct current component, for example from the output of the Difference or quotient generator can be obtained, an absolute measurement of the glucose concentration enables. The amplitude and phase behavior of the high-pass filter is advantageously designed in such a way that that the entire frequency band of pure glucose rotation is restored.

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The absolute determination of the concentration of one or more optically active components, which is possible according to the invention in liquid systems is based accordingly on the fact that the different time-concentration behavior of the individual optically active components by using suitable signal separation methods to differentiate between the relevant Substances and their selective quantitative determination are exploited.

The quantitative and at the same time selective determination of optically active substances in very small concentrations also requires a high sensitivity of the determination method or the corresponding device. In conventional polarimeters, the rotation value of the polarized light is determined after passing through the sample with an analyzer which causes a change in the intensity of the light rotated in its plane of polarization (cf. DE-OS 2 724 54-5), since it is only full for light is permeable, which oscillates in its polarization direction. If the plane of polarization of the incident light is rotated by the angle φ to the direction of polarization of the analyzer, the relationship results, since the intensity is proportional to the square of the amplitude

I = Ϊ -cos u; · (1).

For the sensitivity of such conventional polarimeters it follows

Sr = I _o .2-cosp-siny> (2).

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Equation (2) represents the formulaic expression for the known fact that when the plane of polarization is rotated maximum sensitivity results by 4-5 ° to the original polarization direction. With orders with a beam splitter, as known from CH-PS 441 814 and DE-OS 2 724 54-3, the sensitivity is independent of the absolute intensity, and it applies

The sensitivity of conventional polarimeters, in which the rotation of the plane of polarization of the resulting sample Light is determined with an analyzer in relation to the polarization plane of the light in front of the sample, is therefore theoretically limited.

An increase in sensitivity is achieved according to the invention in that the polarized light from the light source, before it reaches the sample, it first passes through a modulator. The signal frequency band emanating from the sample is accordingly modulated twice (double light modulation). The first modulator (e.g. a Faraday modulator) works in the low or high frequency range, depending on which highest frequency the light detectors process can. The simplest example is 1000 Hz. After passing through the sample is the light frequency twice (phase) modulated. This means that demodulation must also be carried out twice. The first demodulation can, for example, by Exploitation of the dependence of the reflection coefficient from the azimuth angle. The resulting low (high) frequency can then be used in an AC amplifier (a selective amplifier or lock-in amplifier) and then demodulated (the second time). To this

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Way can the sensitivity limiting signal-to-noise ratio according to the invention can be improved by at least an order of magnitude.

Instead of phase modulation, the light beam can also have frequency or amplitude modulation, the demodulation device (second demodulator) then having to be adapted to the respective type of modulation is.

Another way to increase sensitivity According to the invention, the analyzer (first demodulator) that was previously regarded as essential with which the

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specimen-related rotation of the polarization plane of the incident light was determined, is omitted: If a polarized light beam, which first passed through the sample and g | f also the modulator, hits a plane-parajlele plate, which also serves as a beam splitter, the reflected intensity is from Angle of incidence oL as well as the azimuth angle ψ , ie the angle of the plane of oscillation of the incident light to the incidence. the portion passing through the plate, i.e. the intensity of the refracted light, is also dependent in a known way on the angle oL (cf. e.g. Bergmann, Schäfer, Lehrbuch der Experimentalphysik, Vol III, (| ptik, V / alter de Gruyter & Co Verlag, Berlin (1966)), with is1
Area c
while c

i remarkable that the reflection coefficient increases sharply above the folarization angle, the permeability coefficient decreases in the specified range,

The sensitivity can be calculated from the change in the reflection coefficient and the transmission coefficient by forming the derivative according to the angle oL. Ip. first approximation it is sufficient to use the reflection. coefficient, since the permeability coefficient changes less strongly with OL . Furthermore, the derivation must be carried out according to the azimuth angle ψ , since only this is changed in the polarimetric measurement. From this it follows for the change in the reflection coefficient as the sensitivity of the

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ORIGINAL INSPECTED

polarimeter according to the invention:

where mean:

$ the reflection coefficient ( ^{plane of oscillation of the p} radiation parallel to the plane of incidence),

oL the angle of incidence of the radiation, to the perpendicular measured

ψ the angle of the incident radiation to the entrance

case level,

φ the angle of the reflected radiation ^r case level for A and

η the refractive index (air-reflecting medium).

The quantitative evaluation of equation (4) for the values η - 1.5, y _e = 5.7 ° and OC - 70 °, taking into account the change in the permeability coefficient, gives the factor 16 for the increase in sensitivity compared to a conventional polarimeter for equation (3) holds; the factor 16 is composed of the factor 8 of the change in the reflection coefficient and the factor 2 of the change in the transmission coefficient. Such a polarimeter according to the invention thus has a sensitivity that is significantly higher than that of conventional polarimeters.

It follows that, according to the invention, the conventional analyzer can be omitted if the reflection is optically thinner or a denser medium is used for the (first) demodulation; the reflected beam can be used as a measuring beam and the refracted beam can be used as a reference beam, although this assignment is not mandatory.

Instead of the plane-parallel plate that was used in the

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The arrangement according to the invention is used as a beam splitter and as a first demodulator can be according to the invention also use a prism. The prism is penetrated in such a way that the polarized light beam emitted by the sample comes, hits a prism surface perpendicularly, so that no reflection occurs. Only at the rear Prism surface towards the thinner medium, the light beam is reflected in a reflected and a refracted one Split beam. The reflected beam is also refracted when it exits the prism. Consequently the result is an arrangement that is basically the same as that explained for the plane-parallel plate; the reflected ray preferably provides the signal voltage, while the refracted beam gives the reference voltage.

This arrangement with a prism has the advantage that the reflection coefficient changes very strongly with the angle <~ X_ given a suitable choice of the prism angle. This results in a further improved sensitivity. Furthermore, with this arrangement, a change in the intensity of the refracted light, ie the change in the transmission coefficient, has no influence, since the prism angles can be selected so that the reference beam and the signal beam leave the prism at the same angle. This is the case, for example, with a prism with angles &>, 2oC and (180 - 3 ot.). The theoretically achievable sensitivity for this case can be calculated from the Fresnel formulas, just like equation (4). The result is the same equation with the only difference that compared to equation (4), instead of the refractive index η, its reciprocal value 1 / n is used. Although the equation obtained in this way corresponds formally to equation (4), it leads to considerably different consequences. For example, the sensitivity for the critical angle of total reflection becomes infinitely great. However, it is already depending on the polarization angle

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Azimuth angle ψ larger by a factor of 3 than when using a plane-parallel plate. Overall, this arrangement results in a resolution that is two orders of magnitude higher than that of conventional polarimeters. The usable resolution (sensitivity) of the arrangement according to the invention depends on the required measuring range of the polarimeter, for example on the maximum change in angle to be measured. If, for example, a measuring range of +0.5 ° is assumed, then arithmetically with n = 1.5> ψ _e = 5> 7 ° and ° * - = 4-1 »2 ° the sensitivity is improved by a factor of 100.

The invention is explained in more detail below with reference to the drawing; show it:

1 to 8: schematic representations of different embodiments of the polarimeter according to the invention

and

Fig. 9: a special construction of the invention Polarimeter for injury-free transcutaneous blood sugar determination.

In the figures, the references ζ aiii en have the following meaning:

1 = a light source that is linearly polarized light

emitted,

2 = first modulator,

3 = sample,

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4 = λ / 4 plate,

5 = beam splitter, first demodulator, analyzer,

6 = analyzer,

7 and 7 * = detector, e.g. photodiode, photo

multiplier, phototransistor, etc.

8 = differential amplifier or quotient generator,

9 = amplifier, second demodulator,

10 = display, output or registration device,

11 = frequency generator,

12 = differentiator,

13 = signal divider,

14 = integrator or direct current adder,

15 = amplifier.

+ and - mean the positive or negative input for a differential amplifier, and the numerator or denominator for a quotient generator

♦ denotes the reference signal. In Fig. 1 is a first inventive device shown in the selection of the rotation value assigned to the component to be determined by a signal divider J_5 takes place, for example a high pass for the Case of glucose determination in the presence of others optically active blood components.

The beam splitting gives an analysis value that is independent of the absolute value of the signal. Both a conventional light source with a polarizer and, for example, a laser or a laser diode can be used as the light source J_. The λ / Μ plate 4 is used to correct the depolarization effect of, for example, irradiated skin or tissue parts lying in the vicinity of the measuring point. The amplifier 1j> corresponds to this

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as ; ■:; ■■ \ - - ,. _

conventional power amplifier.

Fig. 2 corresponds in principle to the anordning of Figure 1, but in addition, a modulator is forge see 2_, which from the frequency generator IJ _-. Is driven!. A Faraday modulator, a light modulator based on the Kerr effect, a light amplitude modulator such as a pulsed laser diode or a phase modulator, that is to say an optical device that changes the length of the light path, can serve as the modulator; The generator 11, which supplies the modulation frequency, is connected to the amplifier 9, which is tuned to the modulation frequency of the frequency generator 21. AIa amplifier 9 can serve, for example, a selective amplifier, in particular a lock-in amplifier. The arrangement of FIG. 2, in which the light beam is modulated before entering the sample and demodulated again after signal processing in the differential amplifier or quotient generator IS Im ₁ amplifier 9, serves to increase the measurement sensitivity.

Fig. 3 corresponds in principle to the device of Fig. 1, the selection of the rotation value ^{increment assigned to the component to be determined on the basis of the different time-concentration characteristic 1} using a differentiator j22, a signal splitter ._ ^ 5, for example a high-pass filter in the in vivo glucose determination, and an integrator 14 is made.

By selecting the rotation value ε associated with the component to be determined from the rotation value increments that are determined by optically active accompanying substances with deviating

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ORIGINAL INSPECTED

29U113

Time-concentration behavior are conditioned, an absolute measurement is accordingly, i.e. the determination the concentration of an optically active component in the presence of other optically active components, made possible, provided that the time-concentration behavior of the component to be determined differs from that of the accompanying components is sufficiently different.

The development of the device according to the invention shown in FIG. 4 differs from that in FIG. 3 represented by the additional modulation by the modulator _2, which is controlled by the frequency generator j1J_, and the demodulation stage of the amplifier _9, which is tuned to the modulation frequency of the frequency generator 1J_ is. Compared to the arrangement of FIG. 3, this arrangement can increase the sensitivity by at least a decade order of magnitude can be achieved, whereby corresponding absolute determinations of optically active components are possible in very small concentrations. The same applies to the arrangement of FIG. 2.

The variant of the apparatus shown in FIG. 5 is based apart from the analog signal division with selection of the rotation value of the component to be determined as in the 1, 2, 3 and 4, on the inventive concept of increasing sensitivity by omission of the conventional analyzer / with simultaneous exchange of measurement and reference branch compared to conventional ones Arrangements with beam splitter and analyzer. As a beam splitter, which, as theoretically explained above, also as a a kind of analyzer acts (as a first demodulator), in Fig. 5 is a plane-parallel plate Ei, which for example consists of crown glass,

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used. The light reflected at the surface of beam is directed to the detector ¹ J., which converts the light intensity into an electrical signal, while the fractional part after passing through the plane-parallel plate impinges on the detector 2JL and generates the reference signal. In Q , the difference or the quotient of the two signals is formed, which, after the explained signal selection of the component to be determined, is displayed and / or recorded in IC).

By appropriate selection of the angle 'x and optionally also by at least partially reflective coating of the plane-parallel plate on the back or front side, the intensity of the two detectors 2 ^ ¹¹ ^ Zl entering radiation set at the same value. The amplifier JIj ?, which can have an adapted phase response (all-pass) for correction, amplifies the signal again in the sense of an output amplifier.

The device shown in FIG. 6 represents a particularly preferred embodiment according to the invention and corresponds to the arrangement of FIG. 5 with the difference that in contrast to the modulation principle according to the invention

, ". ..moduiati, on.sver £ ahren),. -ι. ι ·, (is made twice / in use, whereby the light emitted by the light source is modulated by the modulator controlled by the frequency generator V \ _ and then demodulated again in S ^ in a coordinated manner, whereby the sensitivity can also be increased .

FIG. 7 shows an alternative to the arrangement of FIG Embodiment shown in which as a beam splitter with Analyzer function a prism is used. The reflection takes place differently from the cases of FIGS. 5 and 6, in which the optically denser medium is reflected on

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optically thinner medium. After passing through the sample J5 and the λ / 4 plate 4, the polarized light beam arrives at the prism J5, at the rear boundary surface of which the beam strikes at the angle α to the surface normal. The beam is partially transmitted and partially reflected. The reflected part of the beam is reflected again on the second rear surface and partially transmitted. When exiting the prism, the beam is refracted and hits the detector ¹ J. ^ιαη α generates the signal voltage. The transmitted partial intensity of the first reflection on the rear prism surface reaches the detector 21. ^vn ^ ⁱ generates a reference signal there. The output voltages of the detectors 7. ^{un (} ^ Zl are subtracted or divided in Q , amplified in 9, selected in 1j5 and displayed after final amplification in _10_.

The apparatus that can be achieved by the concept of the invention Simplification is from comparing the devices of FIGS. 5 and 7 with the device of FIG. 2, in each of which a comparable sensitivity is achieved.

The device shown in FIG. 0 represents a further embodiment which is particularly preferred according to the invention and, apart from the additional modulation (modulator 2, frequency generator _1_1_, tuned amplifier 9), corresponds to the device of FIG. 7.

The amplifier Jj> is in the process of performing a frequency band separation theoretically required, but can be omitted if the phase error is approximately taken into account in the calibration curve will:

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Finally, FIG. 9 shows an exemplary embodiment of a device according to the invention in which the optical or polarimetric part a. is miniaturized. The hot part a. can be attached to the ear or earlobe according to this embodiment. The power supply part and signal processing part b is from the polarimetric part a. separated; this part of the device can be accommodated in a jacket pocket, for example. The display is carried out by a display device £ which is designed, for example, in the manner of a wristwatch and can be worn on the wrist; the display device can also be integrated into jewelry such as a bracelet, ring or the like.

The polarimetric optical part of the device according to the invention can be miniaturized or microminiaturized and from the power supply and signal processing part or be separated from the display part, which is particularly advantageous for in-vivo measurements. The polarimetric According to the invention, part can either be attached to a suitable part of the body, as shown in FIG. 9, or carried v / ground or implanted in the body. The display of the concentration of the to be determined optically active substance, for example blood glucose, can be used both in the power supply and in the signal processing part as well as separate from it and be digital or analog. Us is also possible that with an adjustable upper and / or lower signal and thus concentration threshold an acoustic and / or visual warning signal is triggered. Furthermore, the concentration of the substance to be determined or monitored can be, for example by pressing a button or automatically by an optical or acoustic signal. Also ion concentration changes such as a rise or fall in blood sugar can be modified by appropriate modification the device according to the invention is displayed or signaled.

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Claims (1)

BEETZ-LAMPRECHT-BEETZ Steinsdorfstr. 10 D-8000 Munich 22 Telephone (089) 227201 - 227244 - 295910 Telex 5 22048 - Telegram Allpatent Munich Patent attorneys; Üipi-Ing. H? ÖEhYz sen. " Dipl.-Ing. K. LAMPRECHT Dr.-Ing. R. BEETZ jr. LAWYER Dipl.-Phys. Dr. jur. U. HEIDRICH Dr.-Ing. W. TIMPE Dipl.-Ing. J. SIEGFRIED Priv.-Doz. Dipl.-Chem. Dr. rer. nat. W. SCHMITT-FUMIAN Oct. 31, 1979 Expectations ι 1w 1w Method for the quantitative determination of dissolved optically active substances in aqueous or non-aqueous Solutions, especially for the in-vivo determination of blood glucose levels, by polarimetry under - irradiation of the sample with linearly polarized light, - Distribution of the light beam after passing through the sample with a beam splitter into a measuring beam and a reference beam, - Measurement of the intensity of the Heß and the "reference beam" with a detector, - Generation of a difference or quotient signal from the measurement and reference signal and - final amplification of the resulting signal for display or registration, characterized, that for absolute determination at least one optically 709-X-2066-SF / NU 130020/0266 ORIGINAL INSPECTED 29U113 active substance in the presence of other optically active Substances with different frequencies of change in concentration from the resulting difference or quotient signal the signal component (s) with the concentration change frequency the optically active substance (s) to be determined are separated from the other signal components will. ?. Demonstrators according to Claim 1, characterized in that the "signal division by!""Frequency band separation is carried out. 3. The method according to claim 1 or 2, characterized in that the signal division by differentiation and subsequent integration is made. 4. The method according to claim 1 or 2, characterized in that that the signal division is made with a high or low pass. 5. The method according to any one of claims 1 to 4, characterized in that that the signal division by differentiation, subsequent application of a high or low pass and subsequent integration is made. 6. The method according to any one of claims 1 to 5, characterized in that that the polarized light modulates frequency, phase or amplitude before passing through the sample (1st modulation) and the difference or quotient signal formed from the measuring and reference beam in is demodulated in a corresponding manner (2nd demodulation). 7. The method according to claim 6, characterized in that before the second demodulation is amplified with a selective amplifier tuned to the modulation frequency. 130020/0266 8. The method according to claim 7, characterized in that the second demodulation is done with a lock-in amplifier. 9. The method according to any one of claims 1 to 8 »thereby characterized in that for splitting the light beam after the sample and for generating the reflected one Beam and for the first demodulation, the reflection on an optically denser medium is used. 10. The method still claim y, characterized in that that for dividing the light beam after the sample and as the first demodulator a plane-parallel plate is used. 11. The method according to any one of claims 1 to 8, characterized characterized in that for splitting the light beam after the sample and for generating the reflected one Beam and for the first demodulation the reflection on an optically thinner medium is used. 12. The method according to claim 11, characterized in that that to split the beam after the sample as well as First demodulator a prism is used and which is reflected at the interface to the optically thinner medium and at the second interface to the optically thinner medium, the refracted ray as the reflected one Beam is used. 130020/0266 29U113 13. The method according to claim 11 or 12, characterized in that dqß a prism is used which has such angles in the triangular cross-section that the irradiated Light impinges on both interfaces to the thinner medium at the same angle. . Method according to claim 13, characterized in that that a prism is used which has the angles α, 2oL and (180-3oL) in the triangular cross-section. 15. The method according to claim 1o or 14, characterized in that that to achieve the same intensities in the measuring and reference beam a plane-parallel plate oder'a prism with at least partially mirrored Surface is used. 16. The method according to any one of claims 12 to 15, characterized in that a prism i at an angle? '- is used in which a maximum sensitivity of the polarimeter result, the distance of the angle OL from the critical angle of total reflection ^r by the maximum used measuring range is determined. 130020/0266 ORIGINAL INSPECTED 17. Device for performing the method according to one of claims 1 to 16 with a light source (1) for polarized light, a sample part for receiving the sample (3), a beam splitter (5)> One detector each (7 »7 *) for the measuring beam and the reference beam, a differential amplifier or quotient generator (8), a signal amplifier (15) and a display, output or registration device (10), marked by a signal divider (13) for separating the signal component (s) with the frequency of change in concentration the optically active substance (s) to be determined. 18. The device according to claim 17, characterized by a frequency band filter or a crossover as Signal divider (13) 19. The device according to claim 17 »characterized by - A high or low pass filter or a band pass filter (13) and a direct current adder or 130020/0266 - a differentiator (12), a high or low pass or a band pass (13) and an integrator 20. Device according to one of claims 17 to 19, characterized by a plane-parallel plate (5) as a beam splitter and analyzer. 21. Device according to one of claims 17 to 19, characterized using a prism as a beam splitter and analyzer. 22. The device according to claim 21, characterized in that the prism (5) iro triangular cross-section such Has angle that the irradiated light on both interfaces to the optically thinner medium down meets the same angle. 23 · Device according to claim 21 or 22, characterized in that the prism (5) has the angles η , 2 OL and (180-3 dl) in the triangular cross-section. 24. Device according to one of claims 20 to 23, characterized in that the surface of the plane-parallel Plate or the prism (5) is at least partially mirrored. 25. Device according to one of claims 21 to 24, 130020/0266 29AA113 characterized in that the prism (5) has an angle ex at which a maximum sensitivity of the polarimeter results, where the distance between the angle oL and the critical angle of total reflection is determined by the maximum utilized heating range. 26. Device according to one of claims 17 to 25, characterized by a first modulator (2) provided between the light source (1) and the sample (3) as well as a second demodulator (9) arranged after the amplifier 2 ^r /. Vorrichtimp; according to claim 26, characterized by a frequency, phase or amplitude modulator as the first modulator (2). 28. Apparatus according to claim 26 or 27, characterized to the by a selective amplifier before / second demodulator (9). 29. Device according to one of claims 26 to 28, characterized by a lock-in amplifier as a second demodulator (9). 30. Device according to one of claims 26 to 29, characterized in that the second demodulator (9) on the Modulation frequency of the first modulator (2) is tuned. 31. Device according to one of claims 20 to 28, characterized by eliminating a separate analyzer and a device for reflection on the optically thinner or optically denser medium than the first demodulator, whereby the reflected beam, the measuring beam and the refracted one 130020/0266 Are the reference beam. 32. Device according to one of claims 17 to 31 »characterized by a laser or a laser diode as a light source (1) for polarized light. 33 · Device according to one of Claims 17 to 32, characterized through a phase-adjusted power amplifier. 34-. Device according to one of Claims 17 to 33 » by means of digital display such as a digital wristwatch. 35 · Device according to one of claims 17 to 33 » by a printing small computer and a time generator for automatic recording the concentration values of the optically active substance, for example blood glucose. 36. Device according to one of claims 17 to 33, characterized characterized in that the components are provided within a single housing. 37 · Device according to one of claims I7 to 33, characterized by a device for determining the rate of change in the concentration of optically active substance as well as a corresponding 130020/0266 Display or registration device. 38. Device according to one of claims 17 to 33 »characterized by means of a device for triggering an acoustic and / or optical signal for warning when a certain adjustable upper or lower limit value of the concentration of the determined optically active substance. 39 · Device according to one of claims 17 to 33 »thereby characterized in that it is microminiaturized and implanted in a living organism can. 40. Device according to one of claims 17 to 33, characterized characterized in that the optical part (a) ° Ohf or measurement on miniaturized and intended to be worn on the / earlobe is. 4-1. Device according to one of Claims 17 to 4-0, characterized characterized in that it is connected to a control device and controls this directly, which in Depending on the determined concentration of the optically active substance, a liquid enters the body dosed, in particular insulin based on the "determined Blood glucose value. 42. Use of the device according to one of claims 17 to 4-1 for the injury-free determination of the blood glucose level. 130020/0266 4-3. Use of the device according to one of the claims 17 "to 4-1 for injury-free determination and simultaneous regulation of the blood glucose level controlled insulin delivery. 130020/0266